system for plating a conductive substrate, and a substrate holder for holding a conductive substrate during plating thereof

ABSTRACT

A system for plating a conductive substrate is provided. The system comprises a conductive substrate, comprising a first and a second conductive side, wherein said first side of the conductive substrate is to be plated. Furthermore, the system comprises a substrate holder with an attachment means, for attaching the conductive substrate to the substrate holder, such that a first surface of the substrate holder faces the second side of the conductive substrate. The substrate holder also comprises a resilient contact means, attached to the first surface of the substrate holder, said resilient contact means being connectable to a first external potential. The second side of the conductive substrate is provided with an insulating material exposing the second side of the conductive substrate, such that at least one contact area is provided, wherein the resilient contact means is in contact with the exposed second side in said at least one contact area. A substrate holder therefore is also provided.

AREA OF THE INVENTION

The present invention relates to a substrate holder to be used in anelectrolytic plating process. More specifically, the present inventionrelates to a substrate holder comprising a physically adaptable contactmeans arranged to provide electrical contact to cavities on the backsideof an electrically conductive substrate attached to the substrateholder. A method for arranging a substrate in a substrate holder is alsoprovided.

BACKGROUND ART

Electroplating is used for microelectronics in a wide range ofapplications such as interconnects, components, waveguides, inductors,contact pads etc.

A master electrode, such as prepared by the present invention, issuitable for applications involving production of micro and nanostructures in single or multiple layers, fabrication of PWB (printedwiring boards), PCB (printed circuit boards), MEMS (micro electromechanical systems), IC (integrated circuit) interconnects, above ICinterconnects, sensors, flat panel displays, magnetic and opticalstorage devices, solar cells and other electronic devices. It can alsobe used for different types of structures in conductive polymers,structures in semiconductors, structures in metals, and others arepossible to produce using this master electrode. Even 3D-structures insilicon, such as by formation of porous silicon, are possible.

Chemical vapour deposition and physical vapour deposition are processesthat may also be used for metallization, but electroplating is oftenpreferred since it is generally cheaper than other metallizationprocesses and it can take place at ambient temperatures and at ambientpressures.

Electroplating of a work piece takes place in a reactor containing anelectrolyte. An anode, carrying the metal to be plated, is connected toa positive voltage. In some cases, the anode is inert and the metal tobe plated comes from the ions in the electrolyte. The conductivity ofthe work piece, such as a semiconductor substrate, is generally too lowto allow the structures to be plated to be connected through thesubstrate to backside contacts. Therefore, the structures to be platedfirst have to be provided with a conductive layer, such as a seed layer.Leads connect the pattern to finger contacts on the front side. Thefinger contacts are in turn connected to a negative voltage. Theelectroplating step is an electrolytic process where the metal istransferred from the anode, or from the ions in the electrolyte, to theconductive pattern (cathode) by the electrolyte and the applied electricfield between the anode and the conductive layer on the work piece,which forms the cathode.

As stated above, the work piece is usually made of a non-conductivematerial. As the pattern to be plated is located on the front side, itis necessary to apply a voltage to the conductive layer on the frontside. Additional leads and contact areas also have to be located on thefront side since contacting the pattern directly with electrodes woulddisturb the plating process in those areas.

The resulting setup has a number of disadvantages:

-   -   Having contact areas on the front side occupies a lot of space        that could otherwise be used for the pattern to be plated.    -   The contact areas are restricted to the periphery of the work        piece in order to occupy as little space as possible.    -   The plating process takes place at an accelerated rate proximate        the electrodes, resulting in non-uniformity of the        metallization. Plating uniformity would be improved if any        portion of the work piece could be contacted.    -   The finger electrodes applied to the contact areas are submerged        in the damaging, such as corrosive, environment of the        electrolyte during the process, leading to degraded electrodes.    -   Constructing durable electrodes requires complex designs and        expensive materials.

An alternative device and process is described in U.S. Pat. No.6,322,678, wherein a substrate holder is constructed with electrodesthat are applied to contact areas on the backside of a work piece, whichcontact areas are either connected to leads that reach around the edgeof the work piece, or to conducting vias, leading through the substrate.However, U.S. Pat. No. 6,322,678 is still accompanied by the problem ofleads and contact areas occupying space on the front side, since theseleads and contact areas are impossible to coordinate with the intendedplating. Also, the electrodes are fixed in a few locations close to theperiphery of the substrate holder, only to ensure a peripheral contactwith the conductive surface of the work piece intended to be plated,placing demands on the layout of the contact areas and leads of the workpiece in order to ensure their correct placement in the correspondinglocations on the backside of the work piece. Also, the substrate holderaccording to U.S. Pat. No. 6,322,678 is useless for plating ECPR masterelectrodes, especially master electrodes having insulating material alsoon the side not intended for plating, since it cannot be assured thatthe electrodes contact conducting parts of the master electrode. Thesubstrate also has to be carefully aligned with the substrate holder'selectrodes. Still further, the electrodes are arranged, such that theyare slidable through the substrate holder, thus failing to ensureisolation of the back side of the work piece from electrolyte.

SUMMARY OF THE INVENTION

Accordingly, the present invention seeks to mitigate, alleviate oreliminate one or more of the above-identified deficiencies and toprovide an improved substrate holder of the kind referred to.

For this purpose, in a first aspect, a system is provided. The systemcomprises (i) a conductive substrate, comprising a first and a secondconductive side, wherein said first side of the conductive substrate isto be plated; and (ii) a substrate holder, comprising; an attachmentmeans, for attaching the conductive substrate to the substrate holder,such that a first surface of the substrate holder faces the second sideof the conductive substrate; and resilient contact means, attached tothe first surface of the substrate holder, said resilient contact meansbeing connectable to a first external potential; the second side of theconductive substrate being provided with an insulating material exposingthe second side of the conductive substrate, such that at least onecontact area is provided; wherein the resilient contact means is incontact with the exposed second side in at least one contact point insaid at least one contact area.

In another aspect a substrate holder for holding a conductive substrateduring plating thereof is provided. The substrate holder comprises anattachment means, for attaching the conductive substrate to thesubstrate holder, such that a first surface of the substrate holderfaces the second side of the conductive substrate; and resilient contactmeans, attached to the first surface of the substrate holder andconnectable to at least one external potential.

Advantageous features of the invention are defined in the dependentclaims.

BRIEF DESCRIPTION OF DRAWINGS

These and other aspects, features and advantages of which the inventionis capable of will be apparent and elucidated from the followingdescription of embodiments of the present invention, reference beingmade to the accompanying drawings, in which

FIG. 1 is a cross-sectional view of an electroplating processingchamber;

FIGS. 2A-C illustrate exemplary designs of a conductive substrate foruse in conjunction with the present invention;

FIGS. 3A, 3B, and 4 illustrate embodiments of the substrate holderaccording to the present invention;

FIG. 5 illustrate loading/unloading embodiments of the substrate holderaccording to the present invention;

FIG. 6 illustrates aligning embodiments of the substrate holderaccording to the present invention;

FIG. 7 illustrates electrical contacting embodiments of the substrateholder according to the present invention;

FIG. 8 illustrates electrical contacting embodiments of the substrateholder according to the present invention;

FIG. 9 illustrates an electrical contacting embodiment of the substrateholder according to the present invention;

FIGS. 10A and 10B illustrate details of an embodiment of the contactelements of the substrate holder according to the present invention;

FIGS. 11A and 11B illustrate details of embodiments of the contactelements of the substrate holder according to the present invention;

FIGS. 12A and 12B illustrate embodiments of the contact means of thesubstrate holder according to the present invention;

FIGS. 13A and 13B illustrate embodiments of the contact means of thesubstrate holder according to the present invention; and

FIGS. 14A and 14B illustrate embodiments of the contact means of thesubstrate holder according to the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Below, several embodiments of the invention will be described withreferences to the drawings. These embodiments are described inillustrating purpose in order to enable a skilled person to carry outthe invention. However, such embodiments do not limit the invention, butother combinations of the different features are possible within thescope of the invention.

Referring to FIG. 1, illustrated is a cross-sectional overview of anelectroplating processing apparatus 100. The drawing is a sketch of theprinciples of operation of a plating process and is intended toillustrate the role of the substrate holder 101 in such a process.

During an electroplating process according to an embodiment of theinvention a conductive substrate 102 is attached to a substrate holder101. The conductive substrate 102 may be a wafer of conducting and/orsemiconducting materials, for instance a metallic material, or of adoped semiconductor material, such as silicon. The conductive substrate102 may be attached to the substrate holder 101 by an attachment means,sealing off the backside of the substrate from the electrolyte in theelectroplating process. Such attachment means may for example be aclamping ring 104. The clamping ring 104 may be made of a rigidnon-conductive material, such as Teflon.

In one embodiment said conductive substrate 102 comprises at leastpartly of a conducting silicon wafer.

One or several layers or patterns of insulating material may then bearranged on the conductive substrate 102. Alternatively, otherconducting materials may be arranged on the conductive substrate 102.Also, one or several layers or patterns of insulating material may becombined with one or several layers or patterns of conducting materialto pattern the conductive substrate 102.

In one embodiment the substrate holder 101 is made of an insulatingmaterial, such as PP (polypropylene), Teflon, or PEEK(polyetheretherketone), and in another embodiment of a conductingmaterial, such as stainless steel. In a yet further embodiment, thesubstrate holder 101 is primarily of an insulating material but maycomprise one or several conducting parts, different from the contactmeans described further in the present invention. The conductivesubstrate 102 is patterned with an electrically insulating layer 103.The insulating layer 103 forms raised structures between which cavitiesare formed. In said cavities conductive surfaces are exposed onto whicha metal may be deposited during the electroplating process. The bowl 105is constructed with a reservoir 106. During the electroplating processthe reservoir 106 is filled with an electrolyte. The electrolyte ispumped from an external reservoir (not shown), in a gentle flow, throughan anode 107. The anode 107 may be formed as a grating in order not toimpede the flow of electrolyte, up towards the conductive substrate 102,which is submerged below the surface of the electrolyte. The electrolyteis made to flow past the conductive surfaces in the cavities formed bythe insulating layer 103. A voltage is applied between the anode 107,which may be single-pieced or segmented, and the backside of theconductive substrate 102, which exposed conductive surface thereby formsthe cathode in the process. The voltage may be applied between the anode107 and the backside of the conductive substrate 102 via the substrateholder 101, as will be further discussed below. Metal ions are releasedby the anode and are carried by the electrolyte and the applied electricfield towards the exposed conductive surfaces where the metal ions aredeposited as a plated metal layer.

In another embodiment, the anode is inert and the ions are provided onlyfrom the electrolyte. In this embodiment it is preferred to regularlyreplenish with a fresh ionic electrolyte.

According to another embodiment, a permeable membrane (not shown) may bearranged in the bowl between the anode 107 and the substrate holder 101in order to allow a process using two electrolytes, creating a firstcompartment in the bowl, wherein the substrate holder 101 is located,and a second compartment, wherein the anode 107 is located. Thepermeable membrane may be permeable to in-organic substances, such as tothe metal ions resulting from the dissolution of metal at the anode 107and water, but impermeable to organic substances, such as brightenersand suppressors. The second electrolyte may be injected above themembrane in the first compartment, i.e. on the side of the membranewhere the substrate holder 101 is located, and may contain brightenersand suppressors. Since the brighteners and suppressors could degrade atthe anode 107 it may be important that they are separated from the anode107 by the membrane. Introducing the permeable membrane between thesubstrate holder 101 and the anode 107 solves the above-identifiedproblem.

Having flowed past the substrate, the electrolyte is made to overflowthe bowl 105, as indicated by arrow 108, into an externalelectrolyte-collecting sink 109. From the sink, the electrolyte may bereturned to the external reservoir (not shown) to be recirculated intothe process. When recirculated, the electrolyte may possibly first passa control station and/or filter (not shown). The electrolyte may also becollected as waste liquid, which means that it will not be returned tothe process. The process flow selected is chosen based on therequirements of the process in question.

Thus, during the preparation of the master electrode, according toembodiments of the present invention, the substrate holder immerses thesubstrate in the electrolyte and a metal is deposited by electroplatingin the cavities on the front side of the substrate, while keeping thebackside sealed off from the electrolyte. According to one embodimentthe substrate holder 101 may be mounted to a piston 110 and an externalprocess control apparatus (not shown). During the whole process thesubstrate holder 101 may be made to rotate in either direction aroundthe z-axis, as indicated in the FIG. 1. This ensures uniformity of theplating process with regard to variations in the electric field and inthe flow of the electrolyte across the substrate.

The embodiment depicted in FIG. 1 shows the substrate holder 101arranged horizontally, but it is equally possible to use the substrateholder 101 for an electroplating apparatus, such as a tilt plater. In atilt plater the substrate holder may for example be tilted in theinterval of 30° to 60°, such as 45°, with respect to the z-axis. Anotheralternative is to use the substrate holder 101 for an electroplatingapparatus, such as a rack plater. In a rack plater the substrate holder101 is immersed substantially vertically in the electrolyte. The latteralternative may also allow for multiple substrate holders 101 to be usedin parallel simultaneously in the same processing apparatus 100.

External conductors and/or air ducts, represented by the dashed line111, supply power to the electrical contact means (not shown, but beingcomprised in the substrate holder 101) and gas pressure to the substrateholder 101 via the piston 110, respectively. Due to the rotatingmovement of the piston, electrical contact to the at least one externalpower source may need, but not necessarily always, to be establishedthrough brush contacts, sliding contacts, or similar frictional contactmeans as deemed appropriate by a person skilled in the art.

The purpose of said air ducts is to supply the substrate holder 101 witha gas pressure, e.g. for applications such as the attachment of asubstrate 102 to the substrate holder 101, for the loading/unloading ofa substrate 102 into or out of the substrate holder 101 or for actuatingthe movement of the clamping ring 104, etc.

Conductors and/or air ducts 111 may be routed from the piston 110 to anexternal unit 112 that comprises a collection of devices, such as atleast one device selected from the group comprising a power supply, agas pump, a user interface, such as a computer by which an operator maycontrol the different parts of the apparatus and/or the process.

Referring to FIG. 2A-B, illustrated are a number of exemplaryembodiments of the conductive substrate 102 and the patterned insulatinglayer 103. The insulating material 103 may be provided on a firstportion of the side of the conductive substrate 102 facing the substrateholder. Thus, the backside insulating layer 103A may be patterned todivide the backside into one or more contact areas 203, at a secondportion of said side of the conductive substrate 102. The pattern on thebackside is usually, but not necessarily always, in the shape ofconcentric circles or circle segments. The area in the middle, i.e. thecenter of the backside, is usually, but not necessarily always, leftexposed to form one contact area. It is also within the scope of thisembodiment that the whole backside is left exposed to form a singlebackside contact area 203, as further described in relation to FIG. 2C.The patterned backside brings about the beneficial technical effect thatmaster electrodes for ECPR, provided with pre-deposited material incavities on the front side, may be connected to several voltages, fromthe different contact areas formed on the backside. This results in apossibility to control and assure an even distribution of platingefficiency over the entire master electrode. It is thus convenient tohave also the backside patterned.

In an embodiment, the back side of the conductive substrate is providedwith an insulating material forming at least one cavity exposing thefront side of the conductive substrate, such that the at least onecontact area is provided in said cavity. Thus, the first and the secondportions of said back side of the conductive substrate are arranged suchthat said insulating material forms at least one cavity, wherein said atleast one contact area 203 is provided in said cavity.

In one embodiment at least one contact area 203 covers at least 50% of adiagonal of the backside of the conductive substrate 102. In thisrespect at least 80%, such as at least 95%, of the diagonal of thebackside of the conductive substrate 102 may be covered by contact areas203. In this way an even distribution of voltages may be provided,ensuring an even plating height and plating speed on the front side.Also, this embodiment provides the technical effect that one specificbackside pattern may interact with different configurations of contactmeans 304, according to below.

It is to be understood that the resistivity of the conductive substrate102 in a lateral direction may be large enough, or that the lateralspacing between contact areas of different potentials, or betweencavities on the front side, may be large enough to yield differentpotentials in at least two points along a radius on the front side ofthe conductive substrate 102.

The front side insulating layer 103B is patterned with the layout to bereplicated when the substrate is used as a master electrode in anelectrochemical pattern replication (ECPR) process. The cavities formedby the front side insulating layer 103B are pre-arranged (in an earlierprocess) with one or more layers of a substantially inert (in saidelectrolyte) conductive material 201, hereafter called electrode layer.The electrode layer may be of a material selected from the groupcomprising Au, Ti, TiW, Cr, Ni, Si, Pd, Pt, Rh, Co and/or alloys orheterogeneous mixtures thereof. During the electrolytic process,represented by the arrows 202, a metal is deposited on said pre-arrangedelectrode layer 201.

A conductive substrate allows the use of an edge insulating layer 103C,comprising at least one layer of at least one electrically insulatingmaterial, covering the edge of the conductive substrate 102. The purposeof the edge insulating layer 103C is to provide electrical insulationbetween the conductive substrate and a target wafer when said conductivesubstrate is used as a master electrode in an electrochemical patternreplication (ECPR) process. Another purpose of the edge insulating layeris to provide an air-tight seal together with the substrate holder 101and to provide a surface that allows mechanical handling during theprocess, such as gripping by the substrate holder 101 or gripping by arobotic arm for loading or unloading of the wafer in the substrateholder 101. The edge insulating layer 103C is also used to form anair-tight seal together with a gasket when the substrate 102 is mountedon the substrate holder 101 during the process, in order to prevent theelectrolyte from coming into contact with the backside of the substrate.It is preferable for the edge insulating layer 103C to cover at least 1to 10 mm from the edge of the substrate.

Another advantage of the edge insulating layer 103C is during the use ofthe substrate 102 as a master electrode in a subsequent ECPR process.When the master electrode is pressed to a substrate being patterned, theedge insulating layer 103C ensures that the substrate being patterned isnot short-circuited along the edge.

Referring to FIG. 2C, illustrated is another exemplary embodiment of theconductive substrate 102. In this embodiment the whole backside is leftexposed to form a single backside contact area 203 in a second portionof the side of the conductive substrate facing the substrate holder. Thefront side has been structured and an electrode layer 201 is arranged inthe depressions. The sidewalls are covered by an insulating layer 103B.

Referring to FIGS. 3A and 3B, illustrated are embodiments of thesubstrate holder 101 and the working principles of the physicallyadaptable contact means 304 according to the present invention. Thephysically adaptable contact means may be any electrical contact meansthat is electrically insulated from the substrate holder 101, exceptfrom any further described interconnections that are arranged to provideelectrical contact between said electrical contact means 304 and anyexternal power supply. Further interconnections may for example be leadspassing through or around the substrate holder 101. Such physicallyadaptable contact means may adapt to—and establish electrical contactwith—a structured surface in a vertical direction, while at the sametime covering a substantial surface area of a substrate in a lateraldirection. Since a subsequent ECPR process requires a certain stepheight between the surface of the insulating layer (e.g. such as theedge insulating layer 103C) and the bottom of the cavities, it alsobecomes necessary to be able to make good electrical contact to thebackside of the substrate 102. This is ensured by the use of thephysically adaptable contact means 304 of the substrate holder 101. Thecontact means 304 may for example be physically adaptable by beingresilient and attached to the surface of the substrate holder intendedto face the backside of the substrate 102. When the contact means 304are resilient and attached to the surface of the substrate holder 101,the electrical contact to the external power supply may be assured byleads passing through or around the substrate holder 101. When theelectrical contact to the external power supply is assured by leadspassing through the substrate holder 101, the leads may be integratedwith the substrate holder 101, such that the leads are not movablewithin the substrate holder. This ensures a good sealing effect betweenan inner space 306 and the environment surrounding the substrate holder.

Regardless of the layout or thickness of a pattern of the insulatinglayer 103A, 103C on the backside of the substrate 102, an operator ofthe present invention may be certain of making contact with any exposedcontact areas 203 using the substrate holder 101, equipped with thephysically adaptable contact means 304, illustrated by the arrows inFIGS. 3A and 3B. The arrows are only intended to show the principle ofvertical adaptation and lateral coverage. The arrows of FIGS. 3A and 3Bdo not represent any physical device.

Typically, if not the whole backside is to be contacted, the physicallyadaptable contact means may connect at the backside of the conductivesubstrate 102 to at least two contact areas 203, or two contact pointsalong a distance from the centre of the conductive substrate to theperipheral edge of the conductive substrate. These at least two contactareas 203 may be located along at least one radius. By contacting thebackside of the substrate 102 in at least two contact areas 203 along atleast one radius the current is distributed more evenly, which allows ahigher rate of plating than only one contact area 203 along at least oneradius. Thus, a first portion of the side of the conductive substratefacing the substrate holder is provided with an insulating material103A, 103C, and a second portion of the side of the conductive substratefacing the substrate holder forms at least one contact area 203; whereinthe resilient contact means 304 is in contact with at least one contactpoint in said at least one contact area.

In an embodiment the arrangement of the contact means 304 is patterned,such that several contact points are provided on the front side of theconductive substrate.

Referring to FIG. 3A, the conductive substrate 102 is normally securedto the substrate holder 101 with a clamping ring 302. The clamping ringcan be made of a rigid, insulating and inert material, such as PP(polypropylene), Teflon, PEEK (polyetheretherketone), or a metal orceramic ring coated with mentioned insulated inert materials. In FIG. 3Athe clamping ring 302 is mounted by screwing it onto the substrateholder 101 by threaded surfaces on the vertical interface between theclamping ring 302 and the substrate holder 101. The lower part of theclamping ring 302 may be provided with a slanting, low-profile structure305. This design brings about the technical effect that the clampingring 302 will reduce the disturbance or hindering of the flow of theelectrolyte in the vicinity of the front side of the substrate 102. Thedistance d should preferably be in the range of less than 10 mm, such asless than 5 mm, for instance less than 2 mm.

The clamping ring 302 may have any suitable peripheral orcircumferential form, as long as it is adapted for the substrate holder101 and the substrate 102, for which the clamping ring is intended.Thus, the peripheral or circumferential form may be circular, square,rectangular, or polygonal.

In order to ensure that no electrolyte leaks to the backside of thesubstrate, gaskets 303A-C may be provided. Furthermore, as disclosedabove, the contact means 304 may be attached to the surface of thesubstrate holder 101, with integrated leads in the substrate holder,said leads connecting the contact means and external power supply, toensure that no electrolyte leaks to the backside of the substrate. Thegaskets 303A-C may be lip seals, double lip seals or o-rings. Gasket303A seals the inner space 306 between the substrate holder 101 and theconductive substrate 102. During or before/after operation the innerspace 306 may be evacuated of air to a pressure <1 atm through air ductsin the substrate holder 101 and in the piston 110 (not shown). Theunderpressure is established to secure the substrate 102 to thesubstrate holder 101.

It is also feasible, according to another embodiment of the presentinvention, to secure the substrate 102 to the substrate holder 101, bymechanically pressing the clamping ring 302 towards the substrate holder101. This may be accomplished by providing a screw vice action betweenthe substrate holder 101 and the clamping ring 302, for example by meansof a screw/bolt configuration known to the skilled artisan. Preferably,the screw/bolt configuration is then covered by an insulating materialafter arrangement, to escape electroplating on said configuration, whensaid configuration is of a conducting material.

An additional pressure chamber (not shown) may be provided in the bulkof the substrate holder 101. The purpose of this chamber, which isdirectly connected by ducts to the inner space 306, is to safeguard theattachment of the substrate 102 against unexpected pressurefluctuations, for instance due to leaks in the valves of the duct system(not shown). The underpressure can be provided to the air ducts from anexternal source, such as a vacuum pump. A valve may be arranged betweensaid external source and said air ducts. In one embodiment,underpressure is continuously provided to the air ducts duringprocessing, to ensure that a desirable underpressure is achieved, evenif there are unexpected leaks through any valves or gaskets. In anotherembodiment, said valve is open to provide underpressure when loading orunloading the substrate, but closed during the electroplating operation,which can reduce the risk of flowing electrolyte into the vacuum system,in the unexpected event of leaks. The underpressure may also be providedthrough a detachable connector. In this case the substrate holder maycomprise a check valve for ensuring that the underpressure ismaintained. The outer space 307 is sealed off from the outsideenvironment by gaskets 303B and 303C and from the inner space by gasket303A. In one embodiment the gas over or underpressure line may beprovided with a ball bearing valve, whereby the substrate holder may berotated without rotating the pressure supplying means. The outer space307 may optionally be increased to a pressure >1 atm, e.g. byintroducing compressed air or preferably a substantially inert gas suchas nitrogen gas, in order for the outer space 307 to act as anadditional safeguard against the electrolyte leaking through gaskets303B and 303C. Pressure sensors (not shown) may also be arranged tomonitor the pressures of the inner space 306 and the outer space 307 inorder to provide a measured value to the external unit 112 and to warnan operator or to automatically initiate precautionary measures in thecase of unforeseen pressure fluctuations. Measures may include automaticcorrection of the pressure or abortion or pausing of the process.

The conductive substrate 102 may also be attached to the substrateholder 101 solely by the clamping ring 302, as described above, in whichcase also the inner space 306 may be provided with an increasedpressure, for instance by using nitrogen gas.

The nozzles 308 of the air ducts may be shaped as grooves or holes inthe front surface of the substrate holder 101. The nozzles 308 may belaid out in patterns of concentric circles or radial lines, or acombination of both. Different pressures may be applied to differentnozzles 308 or groups of nozzles 308 of different radial position, i.e.the applied pressure may be equal along concentric circles of thesubstrate holder 101.

Referring to FIG. 3B, illustrated is a cross-section of an embodiment ofpresent invention wherein the conductive substrate 102 is attached tothe substrate holder 101 by underpressure alone. Gasket 303A seals theinner space 306 from the electrolyte.

Referring to FIG. 4, illustrated is another embodiment of the inventionwherein an underpressure is established in the inner space 306. Thepressure is sufficiently small to bend the conductive substrate 102towards the substrate holder 101. Electrical contact may thereby beestablished with a contact means (not shown), such as a conductive platethat covers substantially the whole front side of the substrate holder101. In this embodiment the backside of the conductive substrate 102 maybe left more or less completely exposed. In further embodiments,underpressure in the inner space 306 may be used together with anycontact means described in the present invention, in order to improvethe electrical contact between the contact means and the conductivesubstrate 101.

FIG. 4 does not include the clamping ring 302, but it is equallypossible to bend the substrate 102 towards the substrate holder 101while using the clamping ring 302.

Referring to FIG. 5, illustrated is a cross-section of anotherembodiment of the invention. Instead of screwing the clamping ring 302to the substrate holder 101, the clamping ring 302 and substrate holder101 may be linked to each other by guiding elements 501, spaced alongthe periphery of the ring/holder. The clamping ring 302 may thus belowered to a loading/unloading position or raised to a processingposition by an actuator (not shown) such as a linear motor, stepper orrotational motor or by a pneumatic actuator. In a loading/unloadingposition the substrate 102 may be loaded/unloaded automatically by arobotic arm (not shown) or manually by an operator. A loading operationcould be carried out by lifting the substrate 102 into contact withgasket 303A where attachment is secured by an underpressure that issubsequently established according to the description of FIG. 3A.Dropping the substrate onto gasket 303B and lifting it into contact withgasket 303A may also be used to load a substrate 102.

It is preferred that the distance between at least two of the guidingelements 501 is greater than the diameter of the substrate 102 in orderto facilitate the loading and unloading of the substrate 102 into or outof the substrate holder 101.

Another embodiment of the loading/unloading device may be in the form ofpressure actuators 502A and/or 502B which may be connected to said atleast one duct, the pressure actuators being able to hold a conductivesubstrate by underpressure, said pressure actuators being extendable andretractable to bring the conductive substrate into proximity of or awayfrom the first surface of the substrate holder. The pressure actuator502A may for example be vacuum pins or vacuum pads, while pressureactuator 502B for example may be a vacuum chuck. The pressure actuators502A and/or 502B may thus be mounted in the front side of the substrateholder 101. When the substrate 102 is brought into proximity of thesubstrate holder 101, either manually or by a robotic arm, the actuators502A and/or 502B are extended to hold the backside of the substrate 102by vacuum suction. The actuators 502A and/or 502B are then retracted tobring the substrate 102 into contact with gasket 303A. The actuators502A may be arranged in a circle with a maximum internal spacing of120°, such as when having three actuator vacuum pins 502A. The actuator502B, such as a vacuum chuck, may be mounted in the center of thesubstrate holder 101. The actuator 502B has a diameter that is smallerthan the conductive substrate 102. The extension and retraction of theactuators 502A and 502B may be by pneumatic means, or by a linear motor,or stepper motor, or a rotational motor (not shown).

Instead of a clamping ring 302, an edge gripper (not shown), such ashooks or an edge grip ring (different from the clamping ring), may beused to grip the edge of the conductive substrate 102 and to pull itagainst the substrate holder 101 and the gasket 303A.

Referring to FIG. 6, illustrated is a cross-section of anotherembodiment of the invention. The substrate holder 101 and the clampingring 302 are here designed with slanted guiding surfaces 601A and 601B,respectively. The guiding surfaces 601A and 601B are used to align thesubstrate 102 laterally and horizontally with respect to the substrateholder 101 during a loading operation. The substrate holder 101 and theclamping ring 302 may still be provided with gaskets 303A and 303B,respectively. For the sake of clarity, they have been left out of FIG.6.

The clamping ring 302 depicted in FIG. 6 may for example be attached byscrew-fit to the substrate holder 101, as described above. However, itis equally possible to use the design with guiding elements 501, asdescribed in conjunction with FIG. 5.

When a backside insulating layer 103A is used it may be necessary toalign the pattern of the backside insulating layer 103A with the contactmeans of the substrate holder 101 when loading the substrate 102 intothe substrate holder 101.

Referring to FIG. 7, illustrated is an exemplary embodiment of the frontside of the substrate holder 101, and the physically adaptable contactmeans 701.

In one embodiment physically adaptable contact means 701 means that thedevice comprises both contact elements 701A and the interconnectionstructure 701B.

The physically adaptable contact means 701 is here laid out in astar-shaped pattern, with individual contact elements 701A evenly spacedalong interconnection structure 701B. The pattern of the interconnectionstructure 701B may be designed as concentric circles or a combination ofconcentric circles and a star. However, any shape that is able to covera substantial part of the conductive substrate 102 is within the scopeof the present invention. In the embodiment according to FIG. 7A thecontact elements 701A are electrically connected in parallel with eachother, through the interconnection structure 701B. The contact elements701A are then electrically connected in parallel with each other,through the interconnection structure 701B, to a common potential node702. The node 702 may, or may not be, located in the center of thesubstrate holder 101. The node 702 is in turn connected through thepiston 110 to at least one external potential (not shown) as describedin conjunction with FIG. 1. It is equally possible to connect thecontact elements 701A individually, or in groups of at least two contactelements 701A, to different potentials in order to apply differentpotentials to different parts of the conductive substrate 102. In such acase it may be necessary to route a number of conductors through thepiston 110 to at least one external power source to provide differentpotential to different contact elements 701A. Usually when applyingdifferent potentials to different parts of the conductive substrate 102it is preferable to keep the potential of the contact elements 701A, ata certain radius from the center, at a certain level, e.g. to applyvoltage in concentric equipotential circles.

The contact elements 701A may be designed in a number of different wayswithout departing from the concept of the invention. It is howeverpreferred that the common and characterizing feature of all designs isthat the contact elements 701A should be flexible/resilient in avertical direction. Thus enabling establishment of electrical contactwith the backside of a conductive substrate 102, regardless of thestructural topography of the substrate surface. Different designs of thecontact elements 701A will be described more closely in conjunction withFIGS. 9 to 13 below.

Referring to FIG. 8, illustrated is another exemplary embodiment of theinvention, displaying the front side of the substrate holder 101 and thephysically adaptable contact means 701. The device of FIG. 8 differsfrom the device of 7A only in that there is a larger contact element701C in the center. In all other respects the devices are the same andoffer the same alternatives for configuration of electrical connectionsand layout of the physically adaptable contact means 701.

In one embodiment the contact elements 701A is made of a conductivematerial and designed like a hook, which is resiliently flexible in avertical direction. The contact element 701A then makes electricalcontact with the backside of the conductive substrate 102. The contactelement 701A, which is part of the physically adaptable contact means701 is electrically connected in parallel to other similar contactelements 701A through the interconnection structure 701B, for example asdisclosed in FIGS. 7A and 7B. The contact element 701A may then besomewhat compressed, making physical contact with the backsideinsulating layer 103A of the conductive substrate 102.

Referring to FIG. 9, illustrated is another exemplary embodiment of thefront side of the substrate holder 101, and the physically adaptablecontact means 901. The physically adaptable contact means 901 is herelaid out in a star-shaped pattern, with individual contact elements901A, in the form of a conductive resilient tube, connected to theinterconnection structure 901B. The tube may, for instance be made ofconductive rubber. The pattern of the interconnection structure 901B andcontact elements 901A may also be designed as concentric circles or acombination of concentric circles and a star. Any shape that is able tocover a substantial part of the conductive substrate 102 is within thescope of the present invention. In this embodiment the contact elements901A are electrically connected in parallel with each other, through theinterconnection structure 901B, to a common potential node 902 in thecenter of the substrate holder 101. The node 902 is in turn connectedthrough the piston 110 (not shown) to at least one external power source(not shown), as described in conjunction with FIG. 1. It is equallypossible to divide the contact element 901A, along its length, intoshorter, contact segments (not shown), electrically insulated from eachother. The contact segments may then be connected individually or ingroups of at least two contact segments, to different potentials inorder to apply different potentials to different parts of the conductivesubstrate 102. This may improve the voltage distribution in theconductive substrate which can lead to a more uniform rate ofelectroplating material on the conductive substrate. A more uniformplating rate allows plating more material into depressions of theconductive substrate 102 without overfilling certain areas. To avoidoverfilling is crucial if the conductive substrate is to be used as amaster electrode and is being put in contact with a target wafersubstrate in a subsequent ElectroChemical Pattern Replication (ECPR)process, since overfilled material would short circuit the masterelectrode with said target substrate whereas no ECPR process could beperformed. This is especially important when high rates are desirable.In such a case it may be necessary to route multiple conductors throughthe piston 110 to at least one external power source to providedifferent potentials to different segments. Usually, when applyingdifferent potentials to different parts of the conductive substrate 102it is preferable to keep the potential of the contact segments, at acertain radius from the center, at a certain level, e.g. to applyvoltage in concentric equipotential circles.

FIGS. 10A and 10B illustrate the flexibility of the physically adaptablecontact means 901.

Referring to FIG. 10A, illustrated is a detailed view of one of thecontact elements 901A, according to one embodiment. The depictedexemplary embodiment of contact element 901A is made of a relativelysoft, tube-shaped material, which may be conductive or whose surface maybe coated with a conductive, flexible film 1001. The inside 1002 of thecontact element 901A may be hollow or filled with another flexiblematerial. FIG. 10A shows how the contact element 901A makes electricalcontact with the backside of the conductive substrate 102. The contactelement 901A, which is part of the physically adaptable contact means901 is electrically connected in parallel to other similar contactelements 901A through the interconnection structure 701B.

Referring to FIG. 10B, illustrated is a somewhat compressed contactelement 901A, making physical contact with the backside insulating layer103A of the conductive substrate 102.

The contact element 901A may in another embodiment be a spring of aconductive material. The spring may be laid out in a star pattern asdepicted in FIG. 9, but may also be laid out as concentric circles or asa combination of the two. Any other features of the device in FIG. 9,10A and 10B are also applicable to said spring.

Referring to FIG. 11A, illustrated is another view of an exemplaryembodiment of a physically adaptable contact means 1101. Contactelements 1101A comprise micro bellows 1102A, which may be inflated ordeflated by an actuator such as an external pump unit or other pneumaticactuator (not shown), as required. The bellows 1102A may, for instance,be deflated as the substrate is loaded into the substrate holder 101 andthen inflated to establish electrical contact at the contact areas 203.Air conduits 1103 are provided in the substrate holder 101 and connectedto the external pneumatic actuator through at least one valve 1104, viaair ducts in the piston 110 (not shown).

Overpressure or vacuum may in another embodiment be provided to the airconduits through a detachable connector. In this case a check valve canbe used to maintain the vacuum or pressure.

As shown in the figure, the contact elements 1101A are connected inparallel through the interconnection structure 1101B. As describedpreviously, in conjunction with FIGS. 7 to 10, the contact elements1101A may also be connected individually or in groups in order to beable to apply different voltages to different contact elements 1101A orto different groups of contact elements 1101A.

Instead of bellows it would be equally possible to mount the contactelements 1101A on a member that is actuated by a linear motor, steppermotor, or rotational motor.

Referring to FIG. 11B, illustrated is another detailed view of anexemplary embodiment of a physically adaptable contact means 1101. Here,the contact elements 1101A are mounted on resilient springs 1102B. Theresilient springs 1102B are, in a mechanically unstressed state,sufficiently extended to allow the contact elements 1101A to reachcontact areas 203 when a substrate 102 is loaded into the substrateholder 101. As shown in the figure, the contact elements 1101A areconnected in parallel through the interconnection structure 1101B. Asdescribed previously, in conjunction with FIGS. 7 to 10, the contactelements 1101A may also be connected individually or in groups in orderto be able to apply different voltages to different contact elements1101A or to different groups of contact elements 1101A.

Referring to FIGS. 12A and 12B, illustrated is another exemplaryembodiment of the physically adaptable contact means 1201. Contactelements 1201A are mounted on a relatively soft, flexible resilientlayer 1202 that is attached to the substrate holder 101 (not shown).Thus, the resilient layer 1202 is located proximally of the contactelements 1201A, and the contact elements 1201A is located distally ofthe resilient layer 1202. When a substrate 102 is loaded into thesubstrate holder 101 (not shown) the flexible resilient layer will adaptaccording to the pressure from the contact elements 1201A. Contactelements 1201A that make contact with the backside insulating layer 103Apushed into the flexible resilient layer 1202, as shown in FIG. 12B.Other contact elements 1201A will reach into the cavities and makecontact with the contact areas 203.

The contact elements 1201A may be connected in parallel to a commonvoltage or may be connected individually, or in groups of at least twocontact elements 1201A, through the flexible resilient layer 1202, viaan interconnection structure (not shown), to at least one externalvoltage source (not shown).

In one embodiment a flexible conductive film 1203 may be arrangedbetween the contact elements 1201A and the conductive substrate 102,i.e. distally of the contact elements 1201A. The flexible conductivefilm 1203 then acts as an interface between the contact elements 1201Aand the conductive substrate 102. In case different voltages arerequired at different parts of the conductive substrate 102, theconductive film may need to be divided into concentric circles that areelectrically insulated from each other.

Referring to FIGS. 13A and 13B, illustrated is another exemplaryembodiment of the physically adaptable contact means 1301. A rigidconductive layer 1302 is applied to, and electrically connected with thesubstrate holder 101 (not shown). The contact element 1301A is formed asa conductive foil that comprises protruding structures 1303. Thestructures may for instance be flexibly resilient point-like protrusionsor elongated corrugations. Such flexible protruding structures may forinstance be manufactured in a conductive foil by cutting, corrugating,lasercutting, punching, waterjet cutting or by grinding out the desiredstructures on the foil. The protrusions are either created directly bythe shaping process or in a subsequent step where the shaped portionsare deformed/bent to protrude from the flat foil.

When the contact element 1301A is pressed against a substrate 102 thatis loaded into the substrate holder 101 (not shown), the protrusions1303 that make physical contact with the backside insulating layer 103Aare resiliently deformed to allow other protrusions 1303 to reach intothe cavities and establish electrical contact with the contact areas203.

In case different voltages are required at different parts of theconductive substrate 102, both the rigid conductive layer 1302 and thecontact element 1301A may be divided into concentric circles that areelectrically insulated from each other. The resulting contact elements1301A may then be connected in parallel to a common voltage or may beconnected individually, or in groups of at least two contact elements1301A, through the rigid conductive layer 1302, via an interconnectionstructure (not shown), to at least one external voltage source (notshown).

Referring to FIGS. 14A and 14B, illustrated is another exemplaryembodiment of the physically adaptable contact means 1401. A relativelysoft elastic layer 1402 is applied to the substrate holder 101 (notshown). The contact element 1401A is formed as a flat, compliant andconductive foil, applied distally of said elastic layer 1402. When theelastic layer 1402 is pressed against the conductive substrate 102 bythe substrate holder 101 the elastic layer 1402 will resiliently deformto reach into the cavities formed by the backside insulating layer 103A,thereby also pressing the compliant contact element 1401A intoelectrical contact with the conductive substrate 102.

An interconnection structure (not shown) may be arranged on thesubstrate holder 101 and be connected to the contact element 1401Athrough the elastic layer 1402.

In case different voltages are required at different parts of theconductive substrate 102, contact element 1401A may be divided intoconcentric circles that are electrically insulated from each other. Theresulting contact elements 1401A may then be connected in parallel to acommon voltage or may be connected individually, or in groups of atleast two contact elements 1401A, through the elastic layer 1402, via aninterconnection structure (not shown), to at least one external voltagesource (not shown).

Referring now to FIGS. 15A and 15B, illustrated is another exemplaryembodiment of the physically adaptable contact means 1501. The contactelement 1501A is a thin electrically conductive foil that is fixed tothe substrate holder 101 along the periphery by an airtight seal, suchas an o-ring, lip-seal or a glued seal, or with a mechanical fixture,such as a clamping ring. An overpressure may be established in thevolume enclosed between the contact element 1501A and the substrateholder 101 via nozzles (not shown) in the substrate holder 101, i.e.proximally of said contact element 1501A. When the substrate holder 101,together with the pressurized contact element 1501A, is subsequentlypressed against the conductive substrate 102, the contact element 1501Ais deformed to reach into the cavities formed by the back sideinsulating layer 103A, thereby establishing electrical contact with theconductive substrate 102.

Referring now to FIGS. 15C and 15D, illustrated is an alternativeembodiment of the device shown in FIGS. 15A and 15B. Here, the contactelement has been divided into concentric circles that are electricallyinsulated from each other. The resulting contact elements 1501A may thenbe connected in parallel to a common voltage or may be connectedindividually, or in groups of at least two contact elements 1501A,through the substrate holder 101, via an interconnection structure (notshown), to at least one external voltage source (not shown), forinstance connecting various voltages or currents to different individualor groups of contact elements. A trench 1503 may be formed between thecircle segments and valves 1502 may be arranged in the trench in orderto provide an under-pressure outside the volume enclosed between thecontact elements 1501A and the substrate holder 101. Such anunder-pressure may be in addition to the overpressure described above.The purpose of the under-pressure is to improve surface adaptability ofthe contact element 1501A. The contacting parts 701A, 901A, 1001, 1101A,1201A, 1203, 1301A, 1401A and 1501A may be made of a durable, relativelyflexible material of high electrical conductivity, that is resistant tochemicals and corrosion, such as a metal selected from Cu, Au, Pt, Pd,Ti or steel, or of metal alloys. They may also be coated with a metallayer or be made of an insulating material that is coated with a metallayer. The coating may be selected from durable and chemically resistantmaterials, such as Pt, Pd, Ir, Au or mixed conductive oxides.

The interconnection structure 701B, 901B, 1101B and any interconnectionstructure of FIGS. 12, 13, 14 and 15 (not shown) may be provided withresistors, particularly variable resistors, and resistance meters, orany other means as deemed appropriate, in order to exercise control overthe different voltages applied to different parts of the conductivesubstrate 102 while only using one external potential. Control of thevariable resistors and the display of measured values are linked to theexternal unit 112 of FIG. 1.

The interconnection structure 701B, 901B, 1101B and any interconnectionstructure of FIGS. 12, 13, 14 and 15 (not shown) may also be providedwith switches to allow the electrical connection or disconnection ofdifferent parts of the contact means.

Said at least one external power supply or voltage source may havemultiple channels for supplying, and/or controlling, differentpotentials and/or currents to different individual contact means orgroups of contact means.

In any embodiment of the invention it is also possible to introduce anadditional insulating layer or film, which may be patterned, between thesubstrate holder 101 and the conductive substrate 102. The purpose ofsuch an insulating layer or film is to cover certain exposed contactareas 203 should modifications to the backside insulating layer 103A berequired. Said insulating layer may be easily removable or exchangeablein order to easily modify the shape or size of exposed contact areas 203for different applications, such as for different conductive substrateswith different front or back side insulating pattern or conductingmaterial.

The embodiments disclosed in FIGS. 7 to 15 may comprise the air ductsand nozzles 308, disclosed in FIGS. 1 and 3 to 6, and the specificationrelated thereto according to above. Such air ducts and nozzles may belocated behind the layers disclosed in FIGS. 12 to 15, if thesedifferent layers are permeable to air and/or other gases, such asnitrogen. If the layers disclosed in FIGS. 12 to 15 are not permeable toair and/or other gases, such as nitrogen, the different layers may beprovided with locally situated channels through the layers,corresponding to the nozzles 308 in the front surface of the substrateholder 101, whereby pressure or underpressure still may be provided inthe inner space 306, in accordance with the other embodiments describedin connection to FIGS. 1 to 6.

In the same way the embodiments disclosed in FIGS. 7 to 15 may comprisethe pressure actuators 502A and 502B, disclosed in FIG. 5, and thespecification related thereto according to above. Such pressureactuators 502A and 502B may then run in channels through layersdisclosed in FIGS. 12 to 15, whereby the actuators still may grip thesubstrate 102, in accordance with the other embodiments described inconnection to FIG. 5.

Substrate holders according to embodiments of the present invention maybe used for the fabrication and preparation of a master electrode, i.e.an electrode in the form of a conductive substrate on which aninsulating layer forms a pattern of cavities, in which cavities theconductive surface of the substrate is exposed. During the preparationof the master electrode the substrate holder immerses the substrate inan electrolyte and a metal is deposited by electroplating in thecavities on the front side of the substrate, while keeping the backsidesealed off from the electrolyte. In a subsequent electrochemical patternreplication (ECPR) process the substrate is used as a master electrodeto fabricate electronic components, waveguides, etc.

The substrate holder according the invention greatly improves controlover the deposition process by allowing the electrical contact means tophysically adapt to any pattern layout of the substrate and by allowingexact control of the voltage applied to different parts of thesubstrate.

Although the present invention has been described above with referenceto specific illustrative embodiments, it is not intended to be limitedto the specific form set forth herein. Rather, the invention is limitedonly by the accompanying claims and other embodiments than the specificabove are equally possible within the scope of these appended claims.

In the claims, the term “comprises/comprising” does not exclude thepresence of other elements or steps. Furthermore, although individuallylisted, a plurality of means, elements or method steps may beimplemented by e.g. a single unit or processor. Additionally, althoughindividual features may be included in different claims, these maypossibly advantageously be combined, and the inclusion in differentclaims does not imply that a combination of features is not feasibleand/or advantageous. In addition, singular references do not exclude aplurality. The terms “a”, “an”, “first”, “second” etc do not preclude aplurality. Reference signs in the claims are provided merely as aclarifying example and shall not be construed as limiting the scope ofthe claims in any way.

1. A system for plating a conductive substrate, said system comprising:(i) a conductive substrate, comprising a first and a second conductiveside, wherein said first side of the conductive substrate is to beplated; and (ii) a substrate holder, said substrate holder comprising:an attachment means, for attaching the conductive substrate to thesubstrate holder, such that a first surface of the substrate holderfaces the second side of the conductive substrate; and a resilientcontact means attached to the first surface of the substrate holder,said resilient contact means being connectable to a first externalpotential, wherein a first portion of the second side of the conductivesubstrate is provided with an insulating material, and a second portionof the second side of the conductive substrate forms at least onecontact area; wherein the resilient contact means is in contact with atleast one contact point in said at least one contact area.
 2. The systemaccording to claim 1, wherein the first and the second portions of saidsecond side of the conductive substrate are arranged such that saidinsulating material forms at least one cavity, wherein said at least onecontact area is provided in said cavity.
 3. The system according claim1, wherein an edge insulating layer (103C), comprising at least onelayer of at least one electrically insulating material, covers the edgeof the conductive substrate (102).
 4. The system according to claim 1,wherein the at least one contact area covers at least 50% of a diagonalof said first side.
 5. The system according to claim 1, wherein theresilient contact means is in contact with said contact area in at leasttwo contact points along a distance from the centre of the conductivesubstrate to the peripheral edge of the conductive substrate.
 6. Thesystem according to claim 1 or 5, wherein at least one contact area isprovided in the centre of the conductive substrate.
 7. The systemaccording to claim 1, wherein the conductive substrate is sealinglyattached to the substrate holder, such that electrolyte solution isprohibited from contacting the second side of the conductive substrate.8. The system according to claim 1, wherein the insulating material ispatterned, such that several contact areas are provided on the secondconductive side.
 9. The system according to claim 8, wherein the patternis in the shape of concentric circles or circle segments.
 10. The systemaccording to claim 1, wherein the arrangement of said contact means ispatterned, such that several contact points are provided on the secondconductive side.
 11. The system according to claim 1, wherein theattachment means comprises a clamping ring or edge gripper along theperiphery of the substrate holder (101), or a pressure providing meansand an airtight seal, said airtight seal being located along theperiphery of the substrate holder (101).
 12. The system according toclaim 11, wherein the clamping ring (302) or edge gripper and thesubstrate holder (101) are linked to each other by guiding elements(501), spaced along the periphery of the substrate holder (101), saidguiding elements (501) being connected to an actuator, said actuatorbeing adapted to lower to a loading/unloading position and/or raise to aprocessing position.
 13. The system according to claim 1, comprising atleast two contact means, wherein a first resilient contact means isconnectable to the first external potential, and a second resilientcontact means is connectable to a second external potential.
 14. Asubstrate holder for holding a conductive substrate during platingthereof, comprising an attachment means, for attaching the conductivesubstrate to the substrate holder, such that a first surface of thesubstrate holder faces the second side of the conductive substrate; andresilient contact means, attached to the first surface of the substrateholder and connectable to at least one external potential.
 15. Thesubstrate holder according to claim 14, wherein the arrangement of saidcontact means is patterned, such that several contact points areprovided on the second side of the conductive substrate.
 16. Thesubstrate holder according to claim 14, wherein the contact meanscomprises interconnection structure (701B), distributed on the firstsurface of the substrate holder, interconnecting resilient contactelements (701A).
 17. The substrate holder according to claim 16, whereinthe distribution of the interconnection structure (701B) is in a shapeselected from the group consisting of star shape, shape of concentriccircles, or a combination of a shape of concentric circles and a star.18. The substrate holder according to claim 16, wherein the contactelements (701A) are electrically connected in parallel with each other,through the interconnection structure (701B), to a common potential node(702).
 19. The substrate holder according to claim 16, wherein thecontact elements (701A) are flexible/resilient in a directionperpendicular to said first surface.
 20. The substrate holder accordingto claim 14, comprising at least one duct (111) supplying overpressureor underpressure to the contact means (304) or to the space in betweenthe substrate holder (101) and the conductive substrate or to the spacein between the contact means and the substrate holder (101).
 21. Thesubstrate holder according to claim 20, wherein the contact means (304)is movable in the direction perpendicular to said first surface by meansof gas pressure supplied in a bellows of said contact means.
 22. Thesubstrate holder according to claim 20, comprising pressure actuators(502A, 502B), connected to said at least one duct, the pressureactuators being able to hold a conductive substrate by underpressure,said pressure actuators being extendable and retractable to bring theconductive substrate into proximity of or away from the first surface ofthe substrate holder.
 23. The substrate holder according to claim 20,comprising an additional pressure chamber, provided in the bulk of thesubstrate holder (101), and connected to said duct, said additionalpressure chamber being in communication with the contact means (304) orwith the space in between the substrate holder (101) and the conductivesubstrate or with the space in between the contact means and thesubstrate holder (101).
 24. The substrate holder according to claim 14,wherein the contact means (304) are mounted on a member that is actuatedby a linear motor, stepper motor, or rotational motor, such that thecontact means (304) is movable in the direction perpendicular to saidfirst surface.
 25. The substrate holder according to claim 14, whereinthe contact means (304) comprises hooks, loops, or tubes,flexible/resilient in a direction perpendicular to said first surface.26. The substrate holder according to claim 14, wherein the contactmeans (304) may be attached to the first surface of the substrate holder(101), with at least one integrated lead in the substrate holder (101),said at least one lead connecting the contact means and at least oneexternal potential.
 27. The substrate holder according to claim 14,wherein the contact means (1201), comprises contact elements (1201A)mounted on a flexible resilient layer (1202) attached to the firstsurface of the substrate holder (101).
 28. The substrate holderaccording to claim 27, comprising a flexible conductive film (1203),arranged distally of the contact elements (1201A).
 29. The substrateholder according to claim 14, comprising a rigid conducting layer (1302)proximally of the contact means (1301A), said rigid conductive layer(1302) being electrically connected with the substrate holder 101, andwherein the contact means (1301A) is a conductive foil that comprisesdistally protruding conducting contact structures (1303).
 30. Thesubstrate holder according to claim 14, comprising an elastic layer(1402) applied to the first surface of the substrate holder (101),wherein the contact element (1401A) is a compliant and conductive foildistally of said conductive elastic layer (1402).
 31. The substrateholder according to claim 20, wherein the contact means (1501A) is athin electrically conductive foil, fixed to the first surface of thesubstrate holder (101) along the periphery of the substrate holder (101)by an airtight seal, said thin electrically conductive foil establishinga volume in between the first surface of the substrate holder and thethin electrically conductive foil, said volume being connected to atleast one first duct.
 32. The substrate holder according to claim 31,wherein the contact means (1501) is divided into concentric circles,electrically insulated from each other.
 33. The substrate holderaccording to claim 32, wherein a trench (1503) formed between the circlesegments, comprises valves (1502), arranged in the trench, said valvesbeing connected to at least one second duct.
 34. The substrate holderaccording to claim 16, wherein the interconnection structure (701B,901B, 1101B) is provided with at least one resistor.